Catalytic fluorination process of making hydrohaloalkane

ABSTRACT

The present disclosure provides a fluorination process which involves reacting a hydrohaloalkene of the formula R f C—Cl═CH 2  with HF in a reaction zone in the presence of a fluorination catalyst selected from the group consisting of TaF 5  and TiF 4  to produce a product mixture containing a hydrohaloalkane of the formula R f CFClCH 3 , wherein R f  is a perfluorinated alkyl group.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a '371 of PCT Application No. PCT/US2012/064322,which was filed on Nov. 9, 2012 and claims priority of U.S. provisionalapplications U.S. Ser. No. 61/558,081 and 61/558,086, both of which werefiled on Nov. 10, 2011; the contents of both of these provisionalapplications are incorporated by reference.

BACKGROUND

1. Field of the Disclosure

This disclosure relates in general to catalytic fluorination processesof making hydrohaloalkanes. More particularly, this disclosure relatesto fluorination reactions of hydrohaloalkenes with HF using TaF₅ or TiF₄as catalysts.

2. Description of Related Art

Hydrohaloalkanes, such as HCFCs (hydrochlorofluorocarbons), can beemployed in a wide range of applications, including their use as aerosolpropellants, refrigerants, cleaning agents, expansion agents forthermoplastic and thermoset foams, heat transfer media, gaseousdielectrics, fire extinguishing and suppression agents, power cycleworking fluids, polymerization media, particulate removal fluids,carrier fluids, buffing abrasive agents, and displacement drying agents.They are also useful as intermediates to HFOs (hydrofluoroolefins) whichnot only are safe for the stratospheric ozone layer but also have lowglobal warming potentials (GWPs).

BRIEF SUMMARY OF THE DISCLOSURE

The present disclosure provides a fluorination process which comprisesreacting a hydrohaloalkene of the formula R_(f)CCl═CH₂ with HF in areaction zone in the presence of a fluorination catalyst selected fromthe group consisting of TaF₅ and TiF₄ in an amount effective and underconditions to produce a product mixture comprising a hydrohaloalkane ofthe formula R_(f)CFClCH₃, wherein R_(f) is a perfluorinated alkyl groupwithout substantially forming R_(f)CF₂CH₃. These reactions are conductedunder conditions which promote the formation of R_(f)CFClCH₃ andminimize the production of R_(f)CF₂CH₃ and R_(f)CHClCH₂F.

DETAILED DESCRIPTION

The foregoing general description and the following detailed descriptionare exemplary and explanatory only and are not restrictive of theinvention, as defined in the appended claims. Other features andbenefits of any one or more of the embodiments will be apparent from thefollowing detailed description, and from the claims.

As used herein, the terms “comprises,” “comprising,” “includes,”“including,” “has,” “having” or any other variation thereof, areintended to cover a non-exclusive inclusion. For example, a process,method, article, or apparatus that comprises a list of elements is notnecessarily limited to only those elements but may include otherelements not expressly listed or inherent to such process, method,article, or apparatus. Further, unless expressly stated to the contrary,“or” refers to an inclusive or and not to an exclusive or. For example,a condition A or B is satisfied by any one of the following: A is true(or present) and B is false (or not present), A is false (or notpresent) and B is true (or present), and both A and B are true (orpresent).

Also, use of “a” or “an” are employed to describe elements andcomponents described herein. This is done merely for convenience and togive a general sense of the scope of the invention. This descriptionshould be read to include one or at least one and the singular alsoincludes the plural unless it is obvious that it is meant otherwise.

Unless otherwise defined, all technical and scientific terms used hereinhave the same meaning as commonly understood by one of ordinary skill inthe art to which this invention belongs. In case of conflict, thepresent specification, including definitions, will control. Althoughmethods and materials similar or equivalent to those described hereincan be used in the practice or testing of embodiments of the presentinvention, suitable methods and materials are described below. Inaddition, the materials, methods, and examples are illustrative only andnot intended to be limiting.

When an amount, concentration, or other value or parameter is given aseither a range, preferred range or a list of upper preferable valuesand/or lower preferable values, this is to be understood as specificallydisclosing all ranges formed from any pair of any upper range limit orpreferred value and any lower range limit or preferred value, regardlessof whether ranges are separately disclosed. Where a range of numericalvalues is recited herein, unless otherwise stated, the range is intendedto include the endpoints thereof, and all integers and fractions withinthe range.

The term “dehydrochlorinating”, “dehydrochlorination” or“dehydrochlorinated”, as used herein, means a process during whichhydrogen and chlorine on adjacent carbons in a molecule are removed.

The term “alkyl”, as used herein, either alone or in compound words suchas “perfluorinated alkyl group”, includes cyclic or acyclic andstraight-chain or branched alkyl groups, such as, methyl, ethyl,n-propyl, i-propyl, or the different isomers thereof. It includes, forexample, straight or branched chain alkyl groups containing from 1 to 6carbon atoms and cyclic alkyl groups containing 3 to 6 ring carbon atomsand up to a total of 10 carbon atoms.

The term “perfluorinated alkyl group”, as used herein, means an alkylgroup wherein all hydrogens on carbon atoms have been substituted byfluorines. In some embodiments of this invention, the perfluorinatedalkyl group is a perfluorinated C₁-C₆ alkyl group. Examples of aperfluorinated C₁-C₆ alkyl group include —CF₃ and —CF₂CF₃.

The term “product selectivity to CF₃CFClCH₃”, as used herein, means themolar percentage of CF₃CFClCH₃ obtained in the reaction of CF₃CCl═CH₂with HF compared to the total molar amounts of all organic productsobtained.

The term “product selectivity to CF₃CF₂CH₃”, as used herein, means themolar percentage of CF₃CF₂CH₃ obtained in the reaction of CF₃CCl═CH₂with HF compared to the total molar amounts of all organic productsobtained.

The term “regioselectivity to CF₃CFClCH₃”, as used herein, means themolar percentage of CF₃CFClCH₃ obtained in the reaction of CF₃CCl═CH₂with HF compared to the total molar amounts of CF₃CFClCH₃ andCF₃CHClCFH₂ obtained.

The term “without substantially forming R_(f)CF₂CH₃” refers to theformation of R_(f)CF₂CH₃ in substantially small amounts, e.g., in lessthan about 2 mole % relative to the starting material R_(f) CCl═CH₂.

In addition, the term “without substantially forming R_(f)CHClCH₂F”refers to the formation of R_(f)CHClCH₂F in substantially small amounts,e.g., in less than about 5 mole % relative to the starting materialR_(f) CCl═CH₂.

Disclosed is a fluorination process comprising reacting ahydrohaloalkene of the formula R_(f)CCl═CH₂ with HF in a reaction zonein the presence of a fluorination catalyst selected from the groupconsisting of TaF₅ and TiF₄ in an amount effective and under conditionsto produce a product mixture comprising a hydrohaloalkane of the formulaR_(f)CFClCH₃, wherein R_(f) is a perfluorinated alkyl group withoutsubstantially forming R_(f)CF₂CH₃ or R_(f)CHClCH₂F. This reaction is aliquid phase fluorination process.

In some embodiments of this invention, the desired product, i.e.,hydrohaloalkane of the formula R_(f)CFClCH₃, is recovered from theproduct mixture.

In some embodiments of this invention, the hydrohaloalkene startingmaterial is CF₃CCl═CH₂ (i.e., R_(f) is CF₃), and the hydrohaloalkaneproduct is CF₃CFClCH₃.

In some embodiments of this invention, the hydrohaloalkene startingmaterial is CF₃CF₂CCl═CH₂ (i.e., R_(f) is CF₃CF₂), and thehydrohaloalkane product is CF₃CF₂CFClCH₃.

In some embodiments of this invention, the fluorination catalyst isTaF₅. Typically, when the fluorination process is conducted in thepresence of TaF₅, the temperature in the reaction zone is from about 90°C. to about 160° C. In some embodiments of this invention, thetemperature is from about 95° C. to about 160° C. In some embodiments ofthis invention, the temperature is from about 95° C. to about 125° C. Instill additional embodiments, the temperature of the reaction rangesfrom about 98° C. to about 114° C.

Typically, when the fluorination process is conducted in the presence ofTaF₅, the amount of TaF₅ used for the reaction is at least 1 mole % ofthe amount of hydrohaloalkene of the formula R_(f)CCl═CH₂. In someembodiments of this invention, the amount of TaF₅ used for the reactionis at least 10 mole % of the amount of hydrohaloalkene of the formulaR_(f)CCl═CH₂. In some embodiments of this invention, the amount of TaF₅used for the reaction is at least 20 mole % of the amount ofhydrohaloalkene of the formula R_(f)CCl═CH₂. In some embodiments of thisinvention, the amount of TaF₅ used for the reaction can be up to about30 mole % based on the amount of hydrohaloalkene of the formulaR_(f)CCl═CH₂. In some instances, the amount of TaF₅ used for thereaction is no more than 20 mole % of the amount of hydrohaloalkene ofthe formula R_(f)CCl═CH₂. Thus, in embodiments of the present invention,the amount of TaF₅ present in the reaction ranges from about 1 mole % toabout 30 mol % of the hydrohaloalkene. In another embodiment, it rangesfrom about 10 mol % to about 20 mol % of hydrohaloalkene. Thus, inanother aspect of the present invention the amount of TaF₂ used for thereaction is about 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16,17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, or 30 mole % of theamount of hydrohaloalkene.

In some embodiments of this invention, the fluorination catalyst isTiF₄. Typically, when the fluorination process is conducted in thepresence of TiF₄, the temperature in the reaction zone is from about 90°C. to about 200° C. In some embodiments of this invention, thetemperature is from about 120° C. to about 180° C. In some embodimentsof this invention, the temperature is from about 140° C. to about 160°C.

Typically, when the fluorination process is conducted in the presence ofTiF₄, the amount of TiF₄ used for the reaction is at least 1 mole % ofthe amount of hydrohaloalkene of the formula R_(f)CCl═CH₂. In someembodiments of this invention, the amount of TiF₄ used for the reactionis at least 10 mole % of the amount of hydrohaloalkene of the formulaR_(f)CCl═CH₂. In some embodiments of this invention, the amount of TiF₄used for the reaction is at least 35 mole % of the amount ofhydrohaloalkene of the formula R_(f)CCl═CH₂. In some instances, theamount of TiF₄ used for the reaction is no more than 35 mole % of theamount of hydrohaloalkene of the formula R_(f)CCl═CH₂. Thus, inembodiments of the present invention, the amount of TiF₄ present in thereaction ranges from about 1 mol % to about 35 mol % of thehydrohaloalkene. In another embodiment, the amount of TiF₄ presentranges from about 10 mol % to about 30 mol % of the hydrohaloalkene. Inanother aspect of the present invention, the amount of TiF₄ present inthe reaction is about 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15,16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33,34 or 35 mole % of the amount of hydrohaloalkene.

TaF₅ and TiF₄ are commercially available. They can also be made throughreactions of HF with TaCl₅ and TiCl₄ respectively at a temperature offrom about 25° C. to about 180° C. In some embodiments of thisinvention, the temperature is from about 25° C. to about 130° C. In someembodiments of this invention, TaF₅ and TiF₄ are prepared just prior tobeing used in the fluorination processes. For example, in the samereactor used for the fluorination process, TaCl₅ or TiCl₄ can be treatedwith excess amount of HF. HCl generated from the reaction is releasedfrom the reactor, and the resulting TaF₅/HF or TiF₄/HF mixture can beused for the subsequent fluorination reaction.

Typically, the fluorination process of this disclosure is carried out inanhydrous or substantially anhydrous conditions, which means that water,which is detrimental to the reaction, should be excluded as much aspossible from the reaction zone.

Typically, the fluorination process of this disclosure is carried out ina liquid phase. HF, hydrohaloalkene starting material, andhydrohaloalkane product can also function as solvents for TaF₅ and TiF₄catalysts, and the fluorination process can be carried out without anadditional solvent.

In some embodiments of this invention, the fluorination process iscarried out in the presence of an additional solvent. Typically, theadditional solvent is an inert chemical compound and shall not reactwith other chemical compounds or catalysts during the reaction. Suchinert solvents, if used, should boil at a temperature enablingseparation from the unconverted starting materials (HF and R_(f)CCl═CH₂)and from the desired product (R_(f)CFClCH₃). In some embodiments of thisinvention, the suitable inert solvent is a perfluorinated alkane. Insome embodiments of this invention, the suitable inert solvent is a lowmolecular weight nitrile such as acetonitrile and propionitrile. In someembodiments of this invention, the additional solvent is a sulfone suchas sulfolane.

The molar ratio of HF to hydrohaloalkene of the formula R_(f)CCl═CH₂used in the fluorination reaction is typically from about 1:1 to about100:1. In some embodiments of this invention, the molar ratio is fromabout 1:1 to about 20:1. In some embodiments of this invention, themolar ratio is from about 1:1 to about 10:1. In some embodiments of thisinvention, the molar ratio is from about 1:1 to about 5:1. In someembodiments of this invention, the molar ratio is from about 1:1 toabout 2:1.

Typically, the fluorination process of this disclosure is conductedunder autogenous pressure. In some embodiments of this invention, thepressure employed in the fluorination process is from about 100 psig toabout 800 psig. In some embodiments of this invention, the pressureemployed in the fluorination process is from about 100 psig to about 550psig. In some embodiments of this invention, the pressure employed inthe fluorination process is from about 100 psig to about 270 psig.

The fluorination process of this disclosure can be carried out in batchreactors, continuous reactors or any combination of such reactors bymethods known in the art. In some embodiments of this invention, HF andthe fluorination catalyst are pre-mixed before contacting or reactingwith hydrohaloalkene of the formula R_(f)CCl═CH₂. In some embodiments ofthis invention, hydrohaloalkene of the formula R_(f)CCl═CH₂ is fed to areaction zone containing the mixture of HF and the fluorinationcatalyst. In some embodiments of this invention, hydrohaloalkene of theformula R_(f)CCl═CH₂ is co-fed with HF to a reaction zone containing themixture of HF and the fluorination catalyst. In some embodiments of thisinvention, the mixture of HF and the fluorination catalyst is co-fed toa reaction zone with hydrohaloalkene of the formula R_(f)CCl═CH₂. Insome embodiments of this invention, the fluorination catalyst isdissolved in an additional solvent before contacting with HF andhydrohaloalkene of the formula R_(f)CCl═CH₂.

In some embodiments, the present process is conducted in the presence ofonly one of the catalysts described hereinabove. In another aspect ofthe present process, the reaction is conducted in the presence of amixture of the two catalysts described herein, as long as the total moleratios of the catalysts are within the mole ratios of tantalum chloride,as described herein. In an embodiment, the present process is conductedin the absence of rate enhancing reagents, such as those described inU.S. Publication No. 2009/0018377, for example1,1,2-trichloro-1-fluoroethane or trichloroethene. In other aspects ofthe present invention, such rate enhancing reagents may be present.

When R_(f) is CF₃, it was found through experiments that thefluorination process of this disclosure provided high conversion of theCF₃CCl═CH₂ starting material. In some embodiments of this invention, theconversion of CF₃CCl═CH₂ during the fluorination process is at least85%. In some embodiments of this invention, the conversion of CF₃CCl═CH₂during the fluorination process is at least 90%.

When R_(f) is CF₃, it was also found through experiments that thefluorination process of this disclosure produced the CF₃CFClCH₃ productwith high selectivity. In some embodiments of this invention, theproduct selectivity to CF₃CFClCH₃ is at least 90 mole %. In someembodiments of this invention, the product selectivity to CF₃CFClCH₃ isat least 95 mole %. In some embodiments of this invention, the productselectivity to CF₃CFClCH₃ is at least 98 mole %. CF₃CFClCH₃ may befurther fluorinated with HF to form CF₃CF₂CH₃.

The desired hydrohaloalkane product of the formula R₁CFClCH₃ can berecovered by well-known techniques. At the end of the fluorinationreaction, the reaction may be quenched with water. The resulting highlyacidic aqueous phase may be neutralized with a buffer solution, such asphosphates. The organic phase can be separated, dried and distilled torecover the desired hydrohaloalkane product. In some embodiments of thisinvention, the recovered hydrohaloalkane product of the formulaR_(f)CFClCH₃ is at least 95 mole % pure. In some embodiments of thisinvention, the recovered hydrohaloalkane product of the formulaR_(f)CFClCH₃ is at least 98 mole % pure.

The effluent from the fluorination reaction zone is typically a productmixture comprising unreacted starting materials (R_(f)CCl═CH₂ and HF),the catalyst, the desired hydrohaloalkane product of the formulaR_(f)CFClCH₃, and some byproducts. The byproducts may includeunder-fluorinated compound R_(f)CCl₂CH₃ and over-fluorinated compoundR_(f)CF₂CH₃. It was surprisingly found through experiments that thefluorination process, which is conducted as described herein, controlsthe generation of the CF₃CF₂CH₃ byproduct at a low level. When R_(f) isCF₃, it was also found through experiments that the regioselectivity ofthe fluorination reaction of the process, as described herein, was veryhigh. The fluorination reaction between CF₃CCl═CH₂ and HF may generateboth isomers CF₃CFClCH₃ and CF₃CHClCH₂F. It was found that thefluorination process, which was conducted as described herein, generatedsubstantially more CF₃CFClCH₃ than CF₃CHClCH₂F. In some embodiments ofthis invention, the regioselectivity to CF₃CFClCH₃ is at least 95 mole%. In some embodiments of this invention, the regioselectivity toCF₃CFClCH₃ is at least 98 mole %.

In some embodiments of this invention, the product selectivity toCF₃CF₂CH₃ is no more than 2 mole %. In some embodiments of thisinvention, the product selectivity to CF₃CF₂CH₃ is no more than 1 mole%. In other words, under the conditions described herein, the presentprocess produces little, if any, products where the HF fluorinates theterminal carbon in R_(f)CCl═CH₂ and/or where the fluorine atom replacesthe chlorine atom on the non-terminal carbon atom in R_(f)CCl═CH₂ Theconditions described herein, e.g., the mole ratio of the catalyst toR_(f)CCl═CH₂ and the temperature of the reaction makes this reactionuseful in the process of preparing tetrafluoropropenes, including2,3,3,3-tetrafluoropropene (HFO-1234yf).

In an embodiment of the present invention, the fluorination process ofthe present invention is an intermediate process for preparingtetrafluoropropenes, including 2,3,3,3-tetrafluoropropene (HFO-1234yf).

In the first step of the reaction, the chlorohydrocarbon is reacted withHF in the presence of a catalyst under fluorination conditions toproduce CF₃ CCl═CH₂ (HCFC 1233xf). Three alternative reactions areprovided, each with different starting materials. In one reaction,1,1,2,3-tetrachloropropene is the starting material; in the secondreaction, 2,3,3,3-tetrachloropropene is the starting material; while inthe third reaction, 1,1,1,2,3-pentachloropropane is the startingmaterial. In the third alternative the 1,1,1,2,3-pentachloropropane notonly is fluorinated, but the reactant is also dehydrochlorinated toproduce 2-chloro-3,3,3-trifluoropropene (HCFO-1233xf). The second stepof the reaction is the fluorination of HCFO-1233xf in the presence of acatalyst to produce 2-chloro-1,1,1,2-tetrafluoropropane (HCFC-244bb).The third reaction step is in the dehydrochlorination of HCFC 244bb toproduce 2,3,3,3-tetrafluoropropene (HCFO-1234yf).

In the second step of the process, the 2-chloro-3,3,3-trifluoropropene(1233xf) is hydrofluorinated to form 3-chloro-1,1,1,2-tetrafluoropropane(244bb), which is then dehyrochlorinated to form the refrigerant2,3,3,3-tetrafluoropropene (HFO-1234yl). One of the effects of thepresent process is to minimize the formation of1,1,1,2,2-pentafluoropropane (245cb), for the formation of 245cbinterferes with and makes it more difficult to conduct thedehydrochlorination reaction to form 2,3,3,3-tetrafluoropropene(HFO-1234yf). If too much catalyst is present, the reaction in thesecond step of the process completely fluorinates the HCFO-1233xf andforms 1,1,1,2,2-pentafluoropropane (245cb). If too much R_(f)CCl═CH₂ ispresent, then some of the R_(f)CCl═CH₂ is not fluorinated. However, bymaintaining the reaction under the reaction conditions describedhereinabove, the present process minimizes the formation of1,1,1,2,2-pentafluoropropane (245cb) and CF₃CHClCH₂F(1,1,1,3-terafluoro-2-chloropropane) and maximizes the formation of thedesired product CF₃CClFCH₃.

Thus, another aspect of the present process is to preparetetrafluoropropenes, including 2,3,3,3-tetrafluoropropene (HFO-1234yf)

According to one embodiment, the present invention includes amanufacturing process for making 2,3,3,3-tetrafluoroprop-1-ene using astarting material according to formula I:CX₂═CCl—CH₂X   (Formula I)CX₃—CCl═CH₂   (Formula II)CX₃—CHCl—CH₂X   (Formula III)wherein X is independently selected from F, Cl, Br, and I, provided thatat least one X is not fluorine. In certain embodiments, the compound(s)of Formula I contains at least one chlorine, a majority of the Xs aschlorine, or all Xs as chlorine. In certain embodiments, the compound(s)of formula I include 1,1,2,3-tetrachloropropene (1230xa).

The method generally includes at least three reaction steps. In thefirst step, a starting composition of Formula I (such as1,1,2,3-tetrachloropropene) is reacted with anhydrous HF in a firstvapor phase reactor (fluorination reactor) to produce a mixture of2-chloro-3,3,3-trifluoropropene (1233xf) and HCl. In certainembodiments, the reaction occurs in the vapor phase in the presence of avapor phase catalyst, such as, but not limited to, a fluorinatedchromium oxide. The catalyst may (or may not) have to be activated withanhydrous hydrogen fluoride HF (hydrogen fluoride gas) before usedepending on the state of the catalyst.

While fluorinated chromium oxides are disclosed as the vapor phasecatalyst, the present invention is not limited to this embodiment. Anyfluorination catalysts known in the art may be used in this process.Suitable catalysts include, but are not limited to chromium, aluminum,cobalt, manganese, nickel and iron oxides, hydroxides, halides,oxyhalides, inorganic salts thereof and their mixtures and any one ofwhich may be optionally fluorinated. In one embodiment, the catalyst ischrome oxide, such as for example, Cr₂O₃. Co-catalysts may also bepresent. Combinations of catalysts suitable for the first fluorinationstep nonexclusively include Cr₂O₃, FeCl₃/C, Cr₂O₃/Al₂O₃, Cr₂O₃/AlF₃,Cr₂O₃/carbon, CoCl₂/Cr₂O₃/Al₂O₃, NiCl₂/Cr₂O₃/Al₂O₃, COCl₂/AlF₃,NiCl₂/AlF₃ and mixtures thereof. In one embodiment, the chrome oxide ispresent with a co-catalyst for fluorination reaction. Chromiumoxide/aluminum oxide catalysts are described in U.S. Pat. No. 5,155,082,the contents of which are incorporated herein by reference. Chromiumcatalysts are also described in U.S. Pat. No. 3,258,500, the contents ofwhich are also incorporated by reference. In another embodiment,Chromium (III) oxides such as crystalline chromium oxide or amorphouschromium oxide are used as catalysts, while in another aspect of thepresent invention, the catalyst for this fluorination step is amorphouschromium oxide. One such chromium oxide catalyst that is used in thefirst fluorination step is the activated chromium oxide gel catalyst,described in U.S. Pat. No. 3,258,500. Chromium oxide (Cr₂O₃) is acommercially available material which may be purchased in a variety ofparticle sizes.

The first fluorination reaction, according to the present invention, maybe carried out under atmospheric pressure. In another embodiment, thisreaction may be carried out under pressures of less than or greater thanatmospheric pressures. For example, the process may be carried out, inone embodiment at a pressure ranging from about 0 psig to about 200 psigand in another embodiment, from about 0 psig to about 200 psig and inanother embodiment from about 5 psia to about 100 psia.

The first fluorination reaction is conducted under condition effectivefor the conversion to 1233xf. In an embodiment, the temperature of theprocess may range from about 150° C. to about 400° C., in anotherembodiment from about 180° C. to about 400° C. In another embodiment,the temperature of the process ranges from about 180° C. to about 400°C., while in another embodiment, the temperature of the process isconducted from about 200° C. to about 300° C.

When the compound of formula I is 1,1,2,3,-tetrachloropropene(HFO-1230xa), the mole ratio of HF to 1230xa in step 1 of the reactionranges from about 1:1 to about 50:1 and, in certain embodiments, fromabout 10:1 to about 20:1. The reaction between HF and HCFO-1230xa iscarried out at a temperature from about 150° C. to about 400° C. (incertain embodiments, about 180° C. to about 300° C.) and at a pressureof about 0 psig to about 200 psig (in certain embodiments from about 5psig to about 100 psig). Contact time of the 1230xa with the catalystmay range from about 1 second to about 60 seconds, however, longer orshorter times can be used.

The second step of the process is the hydrofluorination of2-chloro-3,3,3-trifluoropropene (HCFO-1233xf), as described herein, toform 2-chloro-1,1,1,2-tetrafluoropropane (HCFC-244bb).

The third step of the present process is the dehydrochlorination ofR_(f)CFClCH₃, such as, for example, 2-chloro-1,1,1,2-tetrafluoropropane(HCFC-244bb). The hydrohaloalkane product of the formula R_(f)CFClCH₃may be dehydrochlorinated to produce a product mixture comprising ahydrofluoroalkene of the formula R_(f)CF═CH₂. Typically, thehydrohaloalkane of the formula R_(f)CFClCH₃ produced in the fluorinationprocess above is first recovered from the product mixture and thendehydrochlorinated.

In some embodiments of this invention, the dehydrochlorination processis carried out by pyrolyzing R_(f)CFClCH₃to produce R_(f)CF═CH₂. Theterm “pyrolyzing” or “pyrolysis”, as used herein, means chemical changeproduced by heating in the absence of catalyst. The reactor forpyrolysis may be of any shape consistent with the process but ispreferably a cylindrical tube, either straight or coiled. Heat isapplied to the outside of the tube, the chemical reaction taking placeon the inside of the tube. Of note are the reactors wherein the flow ofgases through the reactor is partially obstructed to cause back-mixing,i.e. turbulence, and thereby promote mixing of gases and good heattransfer. This partial obstruction can be conveniently obtained byplacing packing within the interior of the reactor, filling itscross-section or by using perforated baffles. The reactor packing can beparticulate or fibrillar, preferably in cartridge disposition for easeof insertion and removal, has an open structure like that of RaschigRings or other packings with a high free volume, to avoid theaccumulation of coke and to minimize pressure drop, and permits the freeflow of gas. In some embodiments of this invention, R_(f)CFClCH₃ ispyrolyzed at a temperature of from about 400° C. to about 700° C. toproduce a product mixture comprising R_(f)CF═CH₂. Pyrolysis processeshave also been disclosed in U.S. Patent Publication No. 2010-0105967,which is incorporated herein by reference.

In some embodiments of this invention, the dehydrochlorination processis carried out in the presence of a catalyst. Suitable catalysts fordehydrochlorination include carbon, metals (including elemental metals,metal oxides, metal halides, and/or other metal salts); alumina;fluorided alumina; aluminum fluoride; aluminum chlorofluoride; metalssupported on alumina; metals supported on aluminum fluoride orchlorofluoride; magnesium fluoride supported on aluminum fluoride;metals supported on fluorided alumina; alumina supported on carbon;aluminum fluoride or chlorofluoride supported on carbon; fluoridedalumina supported on carbon; metals supported on carbon; and mixtures ofmetals, aluminum fluoride or chlorofluoride, and graphite. Suitablemetals for use on catalysts (optionally on alumina, aluminum fluoride,aluminum chlorofluoride, fluorided alumina, or carbon) include chromium,iron, and lanthanum. Typically, when used on a support, the total metalcontent of the catalyst will be from about 0.1 to 20 percent by weight;and in some embodiments from about 0.1 to 10 percent by weight. In someembodiments of this invention, catalysts for dehydrochlorination includecarbon, alumina, and fluorided alumina. In some embodiments of thisinvention, carbon includes acid-washed carbon, activated carbon andthree dimensional matrix carbonaceous materials. The catalyticdehydrochlorination processes have also been disclosed in U.S. Pat. No.7,943,015, which is incorporated herein by reference.

In some embodiments of this invention, the dehydrochlorination processis carried out by reacting R_(f)CFClCH₃ with a basic aqueous solution toproduce a product mixture comprising R_(f)CF═CH₂. As used herein, thebasic aqueous solution is a liquid that is primarily an aqueous liquidhaving a pH of over 7; the liquid may be a solution, dispersion,emulsion, suspension or the like. In some embodiments of this invention,the basic aqueous solution has a pH of 8 or higher. In some embodimentsof this invention, the basic aqueous solution has a pH of 10 or higher.In some embodiments of this invention, an inorganic base is used to formthe basic aqueous solution. Such inorganic base can be selected from thegroup consisting of hydroxide, oxide, carbonate, and phosphate salts ofalkali, alkaline earth metals and mixtures thereof. In some embodiments,such inorganic base is sodium hydroxide, potassium hydroxide, ormixtures thereof. In some embodiments of this invention, the basicaqueous solution is an aqueous solution of a quaternary ammoniumhydroxide of the formula NR₄OH wherein each R is independently hydrogen,a C₁ to C₁₆ alkyl group, aralkyl group, or substituted alkyl group,provided that not all R are hydrogens. Examples of NR₄OH compoundsuseful in this invention are tetra-n-butylammonium hydroxide,tetra-n-propylammonium hydroxide, tetraethylammonium hydroxide,tetramethylammonium hydroxide, benzyltrimethylammonium hydroxide,hexadecyltrimethyammonium hydroxide, and choline hydroxide. Optionally,R_(f)CFClCH₃ is reacted with the basic aqueous solution in the presenceof an organic solvent. In some embodiments of this invention, theorganic solvent is selected from the group consisting of benzene and itsderivatives, alcohols, alkyl and aryl halides, alkyl and aryl nitriles,alkyl, alkoxy and aryl ethers, ethers, amides, ketones, sulfoxides,phosphate esters and mixtures thereof. Optionally, R₁CFClCH₃ is reactedwith the basic aqueous solution in the presence of a phase transfercatalyst. As used herein, a phase transfer catalyst is intended to meana substance that facilitates the transfer of ionic compounds into anorganic phase from an aqueous phase or from a solid phase. The phasetransfer catalyst facilitates the reaction between water-soluble andwater-insoluble reaction components. In some embodiments of thisinvention, the phase transfer catalyst is selected from the groupconsisting of crown ethers, onium salts, cryptands, polyalkyleneglycols, and mixtures and derivatives thereof. The phase transfercatalyst can be ionic or neutral.

The reactors, packings, distillation columns, and their associated feedlines, effluent lines, and associated units used in applying theprocesses of embodiments of this invention may be constructed ofmaterials resistant to corrosion. Typical materials of constructioninclude Teflon™ materials and glass. Typical materials of constructionalso include stainless steels, in particular of the austenitic type, thewell-known high nickel alloys, such as Monel™ nickel-copper alloys,Hastelloy™ nickel-based alloys and, Inconel™ nickel-chromium alloys, andcopper-clad steel.

In the third step of 1234yf production, the 244bb is fed to a secondvapor phase reactor (dehydrochlorination reactor) to bedehydrochlorinated to make the desired product2,3,3,3-tetrafluoroprop-1-ene (1234yf). This reactor contains a catalystthat can catalytically dehydrochlorinate HCFC-244bb to make HFO-1234yf.

The catalysts may be metal halides, halogenated metal oxides, neutral(or zero oxidation state) metal or metal alloy, or activated carbon inbulk or supported form. Metal halide or metal oxide catalysts mayinclude, but are not limited to, mono-, bi-, and tri-valent metalhalides, oxides and their mixtures/combinations, and more preferablymono-, and bi-valent metal halides and their mixtures/combinations.Component metals include, but are not limited to, Cr³⁺, Fe³⁺, Mg²⁺,Ca²⁺, Ni²⁺, Zn²⁺, Pd²⁺, Li⁺, Na⁺, K⁺, and Cs⁺. Component halogensinclude, but are not limited to, F, Cl⁻, Br⁻, and F. Examples of usefulmono- or bi-valent metal halide include, but are not limited to, LiF,NaF, KF, CsF, MgF₂, CaF₂, LiCl, NaCl, KCl, and CsCl. Halogenationtreatments can include any of those known in the prior art, particularlythose that employ HF, F₂, HCl, Cl₂, HBr, Br₂, HI, and I₂ as thehalogenation source.

When neutral, i.e., zero valent, metals, metal alloys and their mixturesare used. Useful metals include, but are not limited to Pd, Pt, Rh, Fe,Co, Ni, Cu, Mo, Cr, Mn, and combinations of the foregoing as alloys ormixtures. The catalyst may be supported or unsupported. Useful examplesof metal alloys include, but are not limited to, SS 316, Monet 400,Inconel 825, Inconel 600, and Inconel 625.

Preferred, but non-limiting, catalysts include activated carbon,stainless steel (e.g. SS 316), austenitic nickel-based alloys (e.g.Inconel 625), nickel, fluorinated 10% CsCl/MgO, and 10% CsCl/MgF₂. Thereaction temperature is preferably about 300-550° C. and the reactionpressure may be between about 0-150 psig. The reactor effluent may befed to a caustic scrubber or to a distillation column to remove theby-product of HCl to produce an acid-free organic product which,optionally, may undergo further purification using one or anycombination of purification techniques that are known in the art.

Many aspects and embodiments have been described above and are merelyexemplary and not limiting. After reading this specification, skilledartisans appreciate that other aspects and embodiments are possiblewithout departing from the scope of the invention.

EXAMPLES

The concepts described herein will be further described in the followingexamples, which do not limit the scope of the invention described in theclaims.

LEGEND Abbreviation Formula Name 1233xf CF₃CCl═CH₂2-chloro-3,3,3-trifluoropropene 244bb CF₃CClFCH₃2-chloro-1,1,1,2-tetrafluoropropane 245cb CF₃CF₂CH₃1,1,1,2,2-pentafluoropropane 243ab CF₃CCl₂CH₃1,1,1-trifluoro-2,2-dichloropropane 143a CF₃CH₃ 1,1,1-trifluoroethane243db CF₃CHClCH₂Cl 1,1,1-trifluoro-2,3-dichloropropane

Example 1

Example 1 demonstrates that the fluorination reaction of CF₃CCl═CH₂ inthe presence of TaF₅ catalyst has a high CF₃CCl═CH₂ conversion andproduces CF₃CClFCH₃ with high product selectivity and regioselectivity.

Preparation of TaF₅ Catalyst

Under anhydrous conditions, 30 grams (0.084 moles) of TaCl₅ was added toa 1 L Hastelloy™ reactor. The reactor was then evacuated and chargedwith 160 grams of anhydrous HF. The reactor was then heated at 120° C.while stirring for 1.5 hours under autogenous pressures. Then thereactor was cooled to less than 5° C., and HCl gas was removed by slowlyventing the reactor into a caustic scrubber. At the end, a TaF₅/HFmixture was formed in the reactor.

Fluorination Reaction

The fluorination process in this example was run in a batch mode. Theresulting TaF₅/HF mixture above was heated while stirring to 120° C. and100 grams (0.766 moles) of 1233xf was added over a four-minute period.After the addition of all 1233xf the reactor was held at 120° C. for 5hours under autogenous pressure. After 5 hours, the reactor was cooledto room temperature and 300 ml of water was added. The organics wereevaporated from the reactor and collected in a cylinder chilled with dryice. The cylinder contents were analyzed by GC/MS. Results show 93.3%conversion of 1233xf. The product distribution is listed in Table 1below.

TABLE 1 Components GC area % 244bb 90.5 1233xf 6.7 245cb 1.7 243ab 0.9

Example 2

Example 2 also demonstrates that the fluorination reaction of CF₃CCl═CH₂in the presence of TaF₅ catalyst has a high CF₃CCl═CH₂ conversion andproduces CF₃CClFCH₃ with high product selectivity and regioselectivity.

The procedure of Example 1 was followed except that 28 grams of TaCl₅was used for the preparation of TaF₅. After the addition of all 1233xf,vapor samples were taken from the reactor at three-minute intervals andanalyzed by GC/MS. The product distribution is listed in Table 2 belowunder “3 min”, “6 min”, “9 min”, and “12 min” respectively.

After a total two-hour run time, the reactor was cooled to roomtemperature, and 300 grams of water was added to the reactor. Thereactor was heated to 60° C. and the organics were vapor transferredinto a collection cylinder chilled in dry ice. The cylinder contentswere also analyzed by GC/MS. The result is shown in Table 2 below under“Product 120 min”.

TABLE 2 time intervals Product 3 min 6 min 9 min 12 min 120 mincomponents GC area % 143a 0.087 0.047 0.061 0.058 0.021 245cb 0.9780.907 1.631 1.776 6.57 244bb 90.638 84.85 90.447 88.205 87.367 1233xf7.423 8.813 6.937 7.475 5.037 243ab 0.148 1.055 0.242 0.66 0.824 243db0.046 others 0.558 3.927 0.232 1.798 0.126

Example 3

Example 3 demonstrates that the fluorination reaction of CF₃CCl═CH₂ inthe presence of TiF₄ catalyst has a high CF₃CCl═CH₂ conversion andproduces CF₃CClFCH₃ with high product selectivity and regioselectivity.

Preparation of TiF₄ Catalyst

Under anhydrous conditions, 36.23 grams (0.19 moles) of TiCl₄ was addedto a 1 L Hastelloy™ reactor. The reactor was then evacuated and chargedwith 160 grams of anhydrous HF. The reactor was then heated at 120° C.while stirring for 1.5 hours under autogenous pressures. Then thereactor was cooled to less than 5° C. and HCl gas was removed by slowlyventing the reactor into a caustic scrubber. At the end, a TiF₄/HFmixture was formed in the reactor.

Fluorination Reaction

The fluorination process in this example was run in a batch mode. Theresulting TiF₄/HF mixture above was heated while stirring to 150° C. and100 grams (0.766 moles) of 1233xf was added over a four-minute period.After the addition of all 1233xf the reactor was held at 150° C. underautogenous pressure, and vapor samples were taken from the reactor atsixty-minute intervals and analyzed by GC/MS. The product distributionis listed in Table 3 below under “60 min”, “120 min”, “180 min”, and“240 min” respectively.

After a total five-hour run time, the reactor was cooled to roomtemperature, and 300 grams of water was added to the reactor. Thereactor was heated to 60° C. and the organics were vapor transferredinto a collection cylinder chilled in dry ice. The cylinder contentswere also analyzed by GC/MS. The result is shown in Table 3 below under“Product 300 min”.

TABLE 3 time intervals product 60 min 120 min 180 min 240 min 300 mincomponents GC area % 143a 0.053 0.357 0.055 0.058 11.179 245cb 0.2330.745 0.120 0.261 6.150 244bb 86.669 86.777 85.307 85.536 70.530 1233xf12.627 11.717 12.589 12.932 11.811 243ab 0.306 0.403 1.251 1.149 1.112

Example 4

Preparation of TaF₅ Catalyst

A 1 gallon Hastelloy™ C autoclave equipped with a solid PTFE agitatorwas charged with TaCl₅ (500 gm) and HF (908 gm). The temperature of thereactor was raised to 100° C. for a period of 2 hours to convert TaCl₅to TaF₅. The HCl generated was vented during the preparation process.The maximum pressure during the process was 140 psig. At the end, aTaF₅/HF mixture was formed in the reactor.

Fluorination Reaction

The fluorination process in this example was run in a continuous mode.

During the run, the resulting TaF₅/HF mixture above was maintained at atemperature of from 98° C. to 103° C. A starting material mixturecomprising 99.2 mole % of 1233xf, 0.2 mole % of 244bb, and 0.6 mole % ofunknowns was fed into the reactor at an average rate of 0.56 lb/hr,while HF was fed into the reactor at an average rate of 0.33 lb/hr. Thereactor pressure was kept at 130 to 140 psig. Samples were taken fromthe effluent periodically and were analyzed by GC/MS. At the beginning,about 3.1 mole % 245cb was generated. After about 100 hours from theinitiation of the process, the sample analysis indicated that less than0.6 mole % of the 245cb was formed during the fluorination reaction. Atabout 200 hours from the initiation of the process, one sample analysisindicated that only 0.08 mole % of the 245cb was formed during thefluorination reaction. The reactor effluent sample analysis showed thatthe conversion of 1233xf was initially about 95 mole % and graduallydecreased over the first 160 hours of the run down to 92 mole %. Therate of decrease of the 1233xf conversion accelerated after this timeuntil the run was shut down after 243 hours because of lack of 1233xffeed material. The 1233xf conversion at the end of the 243 hours wasabout 77 mole %. The product selectivity to CF₃CFClCH₃ varied from 98.0mole % to 99.9 mole % during the run. The product selectivity toCF₃CFClCH₃ near the end of the run is 99.9 mole %.

Example 5

Preparation of TaF₅ Catalyst

A 1 gallon Hastelloy™ C autoclave equipped with a solid PTFE agitatorwas charged with TaCl₅ (500 gm) and HF (928 gm). The temperature of thereactor was raised to 100° C. for a period of 2 hours to convert TaCl₅to TaF₅. The HCl generated was vented during the preparation process.The maximum pressure during the process was 140 psig. At the end, aTaF₅/HF mixture was formed in the reactor.

Fluorination Reaction

The fluorination process in this example was run in a continuous mode.

During the 1^(st) run, the resulting TaF₅/HF mixture above wasmaintained at a temperature of from 98° C. to 114° C. A startingmaterial mixture comprising 18.2 mole % of 1233xf, 80 mole % of 244bb,and 1.6 mole % of 245cb was fed into the reactor at an average rate of0.57 lb/hr, while HF was fed into the reactor at an average rate of 0.07lb/hr. The reactor pressure was kept at 130 to 200 psig. Samples weretaken from the effluent periodically and were analyzed by GC/MS. At thebeginning, a lot of 245cb was generated. After about 50 hours from theinitiation of the process, the sample analysis indicated that less than0.5 mole % of the 245cb was formed during the fluorination reaction. Atabout 100 hours from the initiation of the process, one sample analysisindicated that only 0.05 mole % of the 245cb was formed during thefluorination reaction. The sample analysis showed that the effluentcontained 3.0 mole % to 5.0 mole % of 1233xf and also showed that 244bbwas the major product during the process. The 1^(St) run lasted for 181hours. The product selectivity to CF₃CFClCH₃ varied from 92.0 mole % to99.9 mole % during the run. The product selectivity to CF₃CFClCH₃ nearthe end of the run is 99.9 mole %.

During the 2^(nd) run, the 1233xf starting material with 99 mole %purity was fed into the reactor at a rate of 0.575 lb/hr, while HF wasfed into the reactor at a rate of 0.375 lb/hr. The reactor temperaturewas maintained at 98° C. to 102° C., and the pressure was kept at 125 to145 psig. During the course of the 2^(nd) run, the 245cb formationdropped from 0.5 mole % to less than 100 ppm, and the unreacted 1233xfincreased from 5 mole % to 20 mole %. The 2^(nd) run lasted for 30hours. The product selectivity to CF₃CFClCH₃ varied from 98.4 mole % to99.9 mole % during the run. The product selectivity to CF₃CFClCH₃ at theinitial period of the run is 98.4 mole %. The product selectivity toCF₃CFClCH₃ near the end of the run is 99.9 mole %.

Note that not all of the activities described above in the generaldescription or the examples are required, that a portion of a specificactivity may not be required, and that one or more further activitiesmay be performed in addition to those described. Still further, theorder in which activities are listed are not necessarily the order inwhich they are performed.

In the foregoing specification, the concepts have been described withreference to specific embodiments. However, one of ordinary skill in theart appreciates that various modifications and changes can be madewithout departing from the scope of the invention as set forth in theclaims below. Accordingly, the specification is to be regarded in anillustrative rather than a restrictive sense, and all such modificationsare intended to be included within the scope of invention.

Benefits, other advantages, and solutions to problems have beendescribed above with regard to specific embodiments. However, thebenefits, advantages, solutions to problems, and any feature(s) that maycause any benefit, advantage, or solution to occur or become morepronounced are not to be construed as a critical, required, or essentialfeature of any or all the claims.

It is to be appreciated that certain features are, for clarity,described herein in the context of separate embodiments, may also beprovided in combination in a single embodiment. Conversely, variousfeatures that are, for brevity, described in the context of a singleembodiment, may also be provided separately or in any subcombination.

What is claimed is:
 1. A process comprising: reacting a hydrohaloalkeneof the formula R_(f)CCl═CH₂ with HF in a reaction zone in the presenceof a fluorination catalyst selected from the group consisting of TaF₅and TiF₄ to produce a product mixture comprising a hydrohaloalkane ofthe formula R_(f)CFClCH₃, wherein R_(f) is a perfluorinated alkyl group,in an amount effective to form R_(f)CFClCH₃ without substantiallyforming R_(f)CF₂CH₃ or R_(f)CHClCH₂F.
 2. The process of claim 1, furthercomprising: recovering said hydrohaloalkane of the formula R_(f)CFClCH₃from the product mixture.
 3. The process of claim 1, wherein R_(f) isCF₃.
 4. The process of claim 3, wherein the product selectivity toCF₃CFClCH₃ is at least 90 mole %.
 5. The process of claim 1, whereinsaid fluorination catalyst is TaF₅.
 6. The process of claim 5, whereinthe temperature in the reaction zone is from about 90° C. to about 160°C.
 7. The process of claim 5 wherein the amount of TaF₅ present rangesfrom about 1 mole % to about 30 mole % of the amount of thehydrohaloalkene.
 8. The process of claim 7 where the amount of TaF₅present ranges from about 10 mol % to about 20 mol % of hydrohaloalkene.9. The process of claim 1, wherein said fluorination catalyst is TiF₄.10. The process of claim 9, wherein the temperature in the reaction zoneis from about 90° C. to about 200° C.
 11. The process of claim 9 whereinthe amount of TiF₄ present ranges from about 1 mol % to about 30 mol %of the amount of hydrohaloalkene.
 12. The process of claim 9 wherein theamount of TiF₄ ranges from about 10 mol % to about 30 mol % ofhydrohaloalkene.
 13. The process of claim 2, further comprising:dehydrochlorinating the recovered hydrohaloalkane of the formulaR_(f)CFClCH₃ to produce a product mixture comprising a hydrofluoroalkeneof the formula R_(f)CF═CH₂.
 14. The process of claim 13, wherein R_(f)is CF₃.
 15. A liquid phase fluorination process for making CF₃CFClCH₃,comprising: feeding HF and an organic feed mixture comprising about 18.2mole % of CF₃CCl═CH₂, about 80 mole % of CF₃CFClCH₃, and about 1.6 mole% of CF₃CF₂CH₃ to a reaction zone containing TaF₅ and HF; and reactingCF₃CCl═CH₂ from the organic feed mixture with HF in the reaction zone toproduce additional CF₃CFClCH₃; wherein the temperature in the reactionzone is from about 98° C. to about 114° C., and the pressure in thereaction zone is from about 130 psig to about 200 psig.
 16. A liquidphase fluorination process for making CF₃CFClCH₃, comprising: feeding HFand CF₃CCl═CH₂ to a reaction zone containing TaF₅ and HF; and reactingCF₃CCl═CH₂ with HF in the reaction zone to produce CF₃CFClCH₃; whereinthe temperature in the reaction zone is from about 98° C. to about 103°C., and the pressure in the reaction zone is from about 125 psig toabout 145 psig.
 17. A process for preparing2,3,3,3-tetrafluoroprop-1-ene comprising: a. providing a startingcomposition comprising at least one compound having a structure selectedfrom Formulas I, II and III:CX₂═CCl—CH₂X  Formula ICX₃−CCl═CH₂  Formula IICX₃−CHCl═CH₂X  Formula III wherein X is independently selected from F,Cl, Br and I, provided that at least one X is not fluorine: b.contacting said starting composition with a first fluorinating agent toproduce a first intermediate composition comprising2-chloro-3,3,3-trifluoropropene and a first chlorine-containingbyproduct; c. contacting said first intermediate composition with asecond fluorinating agent in the presence of a fluorination catalystselected from the group consisting of TaF₅ and TiF₄ to produce a productcomprising 2-chloro-1,1,1,2-tetrafluoropropane without substantiallyforming 1,1,1,2,2-pentafluoropropane or1,1,1,3-terafluoro-2-chloropropane and d. dehydrochlorinating2-chloro-1,1,1,2-tetrafluoropropane to produce a reaction productcomprising 2,3,3,3-tetrafluoroprop-1-ene.
 18. The process according toclaim 17 wherein the product selectivity to CF₃CF₂CH₃ is no more than 2mole %.
 19. The process according to claim 17 wherein said fluorinatoncatalyst TaF₅.
 20. The process according to claim 19 wherein the amountof TaF₅ present ranges from about 1 mole % to about 30 mole % of theamount of 2-chloro-3,3,3-trifluoropropene and the temperature rangesfrom about 90° C. to about 160° C.
 21. The process according to claim 17wherein said fluorination catalyst is TiF₄.
 22. The process according toclaim 21 wherein the amount of TiF₄ present ranges from about 1 mol % toabout 30 mol % of 2-chloro-3,3,3-trifluoropropene and the temperatureranges from about 90° C. to about 200° C.